1. Field of the Invention
This invention relates to the preparation and packaging of foods. More particularly, it relates to the preparation and packaging of an instant mashed potato product in frozen meals.
2. Discussion of the Related Art
Frozen foods, foods packaged in containers that must only be heated before eating, have become extremely popular. Among the most popular foods are frozen meals -combinations of two or more different foods in a single container.
Frozen meals are typically made by preparing each individual food and, consequently, dispensing each food onto an ovenable tray, which is then further packaged and its contents frozen. It is a desideratum to fully prepare and cook each food before dispensing, so that the frozen foods must merely be reheated by the consumer. Control over the taste and other organoleptic properties of the meal is easier to maintain, if the consumer does not have to cook, but only has to reheat the foods.
Among the most popular foods to be included in frozen meals are instant mashed potato products. They are generally made using a batch process, where a single piece of equipment, typically, a low-speed, open-mixer is used for each batch cycle.
The instant mashed potato products are prepared by combining dehydrated potato solids, in the form of flakes or granules, with a slurry containing water, fat, milk, salt and other seasonings in the mixer. The resulting mixture is delivered to a dispensing unit, which feeds the mixture onto trays conveyed by a frozen meal packaging line. The trays then travel along the line to stations where they are sealed, inserted into cartons and their contents frozen.
This conventional process suffers from several drawbacks. For example, room temperature or chilled water is used to make the slurry. Therefore, the temperature of the potato solid/slurry mixture is far below the gelatinization temperature of potato starch (140.degree.-149.degree. F.). It is not until the mixture is heated by the consumer that the instant mashed potatoes are cooked. Even then, however, due to the adverse effect of freezing on the potato solid/slurry mixture, complete hydration of the potato solids does not occur, so that high quality instant mashed potatoes cannot be prepared.
Another shortcoming of the conventional process arises because of its use of open-mixers. A common characteristic of open mixers is the relatively slow movement of their mixing elements (only about 25-60 rpm). The consequence of slow mixing is the substantial mix time of the total batch cycle needed to achieve a mixture free of lumps.
Such a prolonged mechanical treatment of the potato solids ruptures membranes of the potato cells, particularly the fragile cells of dehydrated potato flakes. Membrane breakage results in water leaching out of the cells and leads to a loss of the mashed potatoes' characteristic mealy texture.
A further disadvantage of the slow batch cycle is that a single, open mixer cannot be used efficiently with modern, high-speed, food packaging lines. It is not unusual for such lines to convey trays at the rate of 250-300 trays per minute. Consequently, it is also a desideratum to develop a batch process having a quick cycle time that can be easily integrated into high-speed food packaging lines.
Accordingly, there has existed a definite need for a process for preparing and packaging a frozen, instant mashed potato product having essentially the same flavor and texture as mashed potatoes prepared from fresh-cooked potatoes. There has existed a further need for a process that completely prepares and cooks the mashed potato product prior to packaging, so that the potatoes need merely be reheated by the consumer. There has existed a still further need for a method for preparing a mashed potato product from dehydrated potato solids that minimizes the mechanical treatment of the potato solids and maximizes the mealy character of the mashed potato product. There has existed a still further need for a method for preparing a mashed potato product that can be used with high-speed frozen meal packaging lines. The method in accordance with the present process satisfies these and other needs and provides further related advantages.